Hermann gael fischer



(No Model.)

H. G. FISCHER. KEY.

No. 424,412. Patented Mar. 25, 1890.

WITNESSES:

ATTORNEY UNITED STATES PATENT OFFICE.

HERHANN CARL FISCHER, OF NEV YORK, N. Y.

KEY.

SPECIFICATION forming part of Letters Patent No. 424,412, dated March 25, 1890.

Application filed February 11, 1389. Serial No. 299,448. (No model.)

To (0% whom it may concern.-

Be it known that I, HERMANN CARL FISCHER, of the city, county, and State of New York, have invented a new and Improved Key, of which the following is a full, clear, and exact description.

My invention is an improvement in the class of; so-called Yale locks.

, .The features embodying the improvement will be hereinafter set forth.

Reference is to be had to the accompanyin g drawings, forming a part of this specification, in which similar letters of reference indicate corresponding parts in all the figures.

Figure 1 is a plan view of the key. Fig. 2 is an end elevation of the same. Fig. 3 is a plan view of a modified form of the key. Fig. 4. is an end view of the same. Fig. 5 shows a blank for making the modified form of the key represented in Fig. 6. Fig. 6 shows another modified form of the key. Fig. 7 is a sectional elevation of the lock with the key in place; and Figs. 8, 9, 10, and 11 represent cross-sections of different key-plates.

Theimproved lock Ais provided with a spirally-shaped key B, fitting into a correspondingly-shaped slot or cavity 0 in the plug or roll-back D. The front end of the key is beveled to adapt it to pass beneath the inner ends of the sliding pins or tumblers E when it is pushed into the spiral slot for the purpose of forcing the said pins outward.

The key B is provided with the usual bow F and the blade G, which is provided with ordinary or suitable bittings for engagement with the pins or tumblers E. The blade is in every case bent spirally; but it may have various forms in cross-section. I have illustrated some preferred forms in Figs. 8 to 1.1, inclusive.

In Figs. 1 and 7 the blade G is formed of a single right-hand spiral blade or flange on a central pin, and in Fig. 3 the key is provided with two left-hand spiral flanges on a central pin. In Fig. 6 the central pin is entirely dispensed with and the blade is simply formed into a spiral having suitable bittings on its edge. Theblank from which this key is made is represented in Fig. 5, which clearly shows the bittings on the edge.

By increasing the number of spirals by varying the sectional distances between them, and by adding ordinary or suitable bittings, I am enabled to produce any desired number of different keys, each of which fits only its corresponding slot in the lock.

As spiral keys are not very easy to imitate and the shape of the slot inside of the plug D cannot be detected from the outside, it will be seen that the lock becomes very diflicult of access to unauthorized persons.

Having thus fully described my invention, I claim as new and desire to secure by Letters Patent- 1. A key provided with a spiral blade having bittingsin its edge, substantially as shown and described.

2. A' key comprising a blade made of two or more spiral flanges standing at angles to each other and provided with bittings in their edges for engagement with the pins or tumblers, substantially as shown and described.

3. A key provided with a blade comprising a central pin and one or more flanges held spirally on the said central pin and having beveled outer end, substantially as shown and described.

4. A key provided with a blade comprising a central pin and one or more flanges held spirally on the said central pin and provided with bittings in their edges for engagement with the pins or tumblers, substantially as shown and described.

5. A key provided with ablade comprising a central pin and one or more flanges held spirally on the said central pin, and provided with bittings in their edges for engagement with the pins or tumblers, the said flanges being beveled at their front ends, substantially as shown and described.

HERMANN CARL FISCHER.

itnesses:

THEo. G. HOSTER, O. SEDGWIOK. 

